000 AXNT20 KNHC 190606 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 206 AM EDT FRI AUG 19 2016 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... Tropical Storm Fiona is centered near 17.1N 41.8W at 19/0300 UTC or about 1026 nm W of the Cape Verde Islands, moving NW at 7 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. A cluster of heavy showers is from 16N-20N between 40W and 44W. See latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. ...TROPICAL WAVES... Tropical wave extends from a 1009 mb low near 10N27W to 18N31W, moving W at 15-20 kt within the last 24 hours. Saharan dry air and dust engulf the wave, thus limiting the convection to the vicinity of the monsoon trough W of the low pressure center. The convection is numerous moderate to isolated strong from 07N-12N between 30W and 36W. Environmental conditions are expected to be conducive for gradual development, and a tropical depression could form early next week while the system moves westward across the tropical Atlantic Ocean. Tropical wave extends from 11N to 16N with axis near 57W, moving W at 20 kt within the last 24 hours. Meteosat enhanced imagery and LPW imagery from surface to 850 mb show there is dry air in the wave environment. On the other hand, satellite derived data indicate the wave is in a region of unfavorable deep layer wind shear. Both the dry air and strong shear are hindering convection at the time. Tropical wave in the Caribbean extends from 11N-19N with axis near 73W, moving W at 20-25 kt within the last 24 hours. Shallow moisture accompanies this wave that is in a region of mainly neutral to unfavorable deep layer wind shear. These factors are limiting the convection to isolated showers over Haiti and Western Dominican Republic and northern adjacent waters. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the African coast near 14N17W to 10N27W to 10N43W. The Intertropical Convergence Zone axis extends from 10N43W to Guyana coastal waters near 07N57W. Aside from convection associated with the tropical waves...isolated showers are from 07N-13N E of 29W. ...DISCUSSION... GULF OF MEXICO... Surface ridging continues to extends from the Atlantic across Florida and the Gulf waters N of 22N. In the Gulf, the ridge is anchored by a 1019 mb high centered near 28N85W, which provides gentle variable flow across the NE basin and E-SE gentle to moderate flow elsewhere N of 22N. Over the Bay of Campeche, a surface trough extends from 21N89W to 18N92W and supports moderate to fresh NE flow within 90 nm off the Yucatan Peninsula coast. The trough also supports isolated showers E of 94W and across the Yucatan Peninsula. Dry air subsidence and unfavorable deep layer wind shear support fair weather elsewhere. Mostly gentle to moderate E-SE winds persist and are expected through the weekend ahead. CARIBBEAN SEA... Water vapor imagery continue to show mostly dry air and stable conditions basin-wide. The main feature in the Caribbean is a tropical wave moving across the central basin supporting shower activity over portions of Hispaniola and northern adjacent waters. See the tropical waves sections for further details. The E pacific monsoon trough support scattered showers in the SW basin S of 11N. Isolated showers are in the Yucatan Channel and in the NW basin waters W of 85W associated with a diffluence zone between an elongated upper level low over the SE Gulf of Mexico and an upper ridge over the W Caribbean. Otherwise...fresh to strong trades prevail between 68W-80W. A new tropical wave is forecast to enter the E Caribbean near sunrise today, however no significant convection is expected to develop for the Lesser Antilles. ...HISPANIOLA... A tropical wave moving across the central Caribbean with axis near 73W is accompanied with shallow moisture. The wave is also in a region of mainly neutral to unfavorable deep layer wind shear. These factors are limiting the convection to isolated showers over Haiti and Western Dominican Republic and northern adjacent waters. This shower activity is forecast to cease near sunrise time today. ATLANTIC OCEAN... The main feature in the basin is T.S. Fiona discussed in the special features section. Over the SW North Atlc, an upper level anticyclonic circulation centered near 21N65W is generating diffluent flow on the northern periphery of the ridge to support heavy showers and tstms from 23N-28N between 61W-66W. A weak surface trough is analyzed from 30N73W to 25N78W supporting isolated showers across the northern Bahamas. Otherwise...the remainder of the SW North Atlc is under the influence of weak surface ridging. Farther east...the central and eastern Atlc are influenced by a surface ridge anchored by a 1021 mb high centered near 30N60W. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS